Famciclovir is an antiviral medicine used to treat cold sores (herpes labialis) around your mouth, lips, nostrils or nose. It must be used as soon as possible after the first symptoms of a cold sore appear, eg, tingling, itching, burning, redness, or swelling. Famciclovir shouldn't be used if a hard crust has already formed on your cold sore.
It works by stopping the herpes simplex virus that causes the infection from replicating (making copies of itself). It doesn't cure the infection or kill the virus, but reduces the severity of the infection and helps the cold sore heal faster. The virus that causes this infection continues to live in your body. Read more about what can trigger the virus on the cold sores page.
Famciclovir can be purchased from your pharmacy without a prescription. Talk to your pharmacist to check if it's suitable for you. Famciclovir is available as 500 milligram tablets.